Corrosion behavior and the weak-magnetic-field effect of aluminum packaging paper

Abstract

Aluminum can be absorbed through the digestive system from water and drinks and the food that contains natural traces and processed food or the food cooked in aluminum cookware. Some studies show that the people exposed to high levels of aluminum may develop kidney, bone and brain diseases. Aluminum foil (AlFeSi) is daily used as packaging for food and drugs stored in the refrigerator where an electric motor induces a magnetic field of a few microteslas. The purpose of this work is to study the corrosion behavior of various aluminum packaging foils and the effect of a weak magnetic field on the morphology and the corrosion kinetics in the 0.3 % and 3 % of mass fractions of NaCl solutions. The mean results for various aluminum packaging foils show that localized corrosion is controlled by the electrochemical potentials of different phases constituting the aluminum foil and the concentration of the precipitates from the other phases. The morphology and the corrosion kinetics of aluminum packaging foil in the 0.3 % and 3 % of mass fractions of NaCl solutions are different with and without an application of a weak magnetic field. Electrochemical tests applied to cheese packaging paper show that the introduction of a magnetic field decreases the polarization resistance, the potential of passivation and the value of the open-circuit potential at the beginning of the corrosion; however, its passivation-current density increases at the beginning of the corrosion. The values of the open-circuit potential with and without a weak magnetic field are the same after thirty days of corrosion. Keywords: aluminum packaging foil, weak magnetic field, aluminum alloys, corrosion, passivation Aluminij se lahko absorbira v prebavni sistem iz vode in pija~in iz hrane, ki vsebuje naravne sledi ter obdelane hrane ali hrane, kuhane v aluminijasti posodi. Nekatere {tudije ka`ejo, da ljudje izpostavljeni visokemu nivoju aluminija, lahko zbolijo na ledvicah, kosteh in mo`ganih. Aluminijeva folija (AlFeSi), ki se dnevno uporablja kot embala`a za hrano in zdravila, se hrani v hladilniku, kjer elektromotor inducira magnetno polje jakosti nekaj mikroteslov. Namen {tudije je predstavitev korozijskega obna{anja razli~nih aluminijevih embala`nih folij in vpliv {ibkega magnetnega polja na morfologijo in kinetiko korozije v 0,3 % in 3 % raztopini NaCl. Rezultati ka`ejo, da je pri razli~nih aluminijevih folijah lokalna korozija kontrolirana z elektrokemijskim potencialom razli~nih faz, ki sestavljajo aluminijevo folijo in s koncentracijo izlo~kov drugih faz. Morfologija in kinetika korozije aluminijevih embala`nih folij v 0,3 % in 3 % raztopini NaCl, sta razli~ni pri prisotnosti ali odsotnosti {ibkega magnetnega polja. Elektrokemijski preizkusi, izvr{eni na ovojni foliji za sir, so pokazali, da prisotnost magnetnega polja na za~etku korozije zmanj{a polarizacijsko odpornost, potencial pasivacije in vrednost potenciala odprtega kroga, vendar pa gostota pasivacijskega toka nara{~a. Vrednost potenciala odprtega kroga je po tridesetih dneh enaka, ob pris...

A study of a non‐conventional evaluation of results from salt spray test of aluminum High Pressure Die Casting alloys for automotive components

“…Figure 3 showed the mass loss per unit of area measured from samples exposed to salt spray test for different times. Table 3 shows the corrosion rates at the same observation times expressed in mm/year units, calculated from these weight losses according to Equation (2). As expected, the corrosion rate of EN AC-46000 was much higher than that of EN AC-44400 and EN AC-43500.…”

“…As is well known, some of the tests most frequently used to investigate the corrosion resistance are the potentiodynamic polarization test and neutral salt spray test. [2] Potentiodynamic polarization tests are electrochemical experiments conducted on small laboratory specimens, with a typical size of 100 mm 2 , that give as output a numerical representation of the samples corrosion behavior through a measurement of the E-i relationship. [3] On the other hand, neutral salt spray test is usually performed on industrial produced components in a proper chamber.…”

“…At the moment, the most widely used alloy to manufacture automotive components with good mechanical resistance, is traditional secondary AlSi9Cux alloys. Nevertheless, this class of alloys exhibits a very low ductility, due to the formation of β-phase (AlFeSi) precipitates, [2] and consequently they cannot be used for heavier applications like safety relevant structural pieces. In addition, the corrosion resistance is strongly reduced by iron and copper precipitates.…”